The present invention is directed to a system for collecting a sample possibly containing an analyte of interest and for then testing the sample. The invention is particularly directed to an improved system for detecting an analyte of interest in a fecal sample. Testing for blood in fecal samples, referred to as a fecal occult blood (FOB) test, for example is commonly performed as a screen for colorectal cancer.
A variety of FOB formats are known in the art (see e.g., U.S. Pat. Nos. 3,996,006; 4,225,557; 4,789,629; 5,064,766; 5,100,619; 5,106,582; 5,171,529; and 5,182,191). The majority of such test formats are based on the chemical detection of heme groups present in stool as a breakdown product of blood. In such tests, the pseudoperoxidase nature of the heme group is used to catalyze a colorimetric reaction between an indicator dye and peroxide. The oxygen sensitive dye can be gum guaiac, orthodianisidine, tetramethylbenzidine, or the like, with guaiac being preferred.
Analytes, including analytes present in stool, can also be detected using chromatographic assay systems. Chromatographic assays, and in particular immunochromatographic assays, are frequently used by physicians and medical technicians for rapid in-office diagnosis and therapeutic monitoring of a variety of conditions and disorders. Immunoassays depend on the specific interaction between an antigen or hapten and a corresponding antibody. In immunochromatographic assays, a detecting reagent or particle is linked to an antibody which binds specifically to a molecule to be assayed, forming a conjugate. This conjugate is then mixed with a specimen and, if the molecule to be assayed is present in the specimen, the detecting reagent-linked antibodies bind to the molecule, thereby giving an indication that the molecule is present. The detecting reagent or particle can be identifiable by color, magnetic properties, specific reactivity with another molecule, or another physical or chemical property.
More information regarding such analytical test systems can be found for example in U.S. Pat. Nos. 4,789,629; 5,441,698; 5,877,028; 6,017,767; 6,165,416; 6,168,956; 6,033,627; 5,846,838; 5,747,351 and 6,221,678, all of which are incorporated herein by reference. In order to make use of such systems, of course, a sample to be tested must first be obtained. In the case of samples obtained from a location away from a physician's office or laboratory able to perform an assay, the sample must be appropriately collected and then transported to the test site.
The collection of fecal samples for testing presents particular challenges, both to the individuals providing such samples as well as to the technicians testing them. Samples obtained away from a testing laboratory must be mailed or otherwise transported, and when received at a laboratory need to be handled without exposing technicians to such samples. The collected samples further need to be appropriately tested. There remains a need for better methods and devices for collecting such samples, transferring the samples to test devices, and performing assays, in particular to facilitate the transfer of a sample to a test device while minimizing the possibility of exposure of a technician to the sample.